We've been told that too, mumeeee. We get the opposite as well, where a child chooses not to do a particular subject in case they get the dreaded old bag (a lot of Y9s have heaved a huge sigh of relief because a language is compulsory at ours and one of the language teachers is retiring this term )
The person who always used to do the timetabling for the whole school was a confirmed bachelor - I don't think anyone else had the time! (I don't know how they do it now - mb, is it computerised? Incredibly complicated, esp in a school which does A levels too, but on a different site)